Technique for automatically preparing a dialysis machine at a predetermined date and time

ABSTRACT

A technique for automatically cleaning, disinfecting and otherwise preparing a dialysis machine includes a method and apparatus for programming the dialysis machine to awaken from a reduced power mode at a predetermined time and perform one of several wake-up procedures (e.g., rinsing, dialysate preparation, or hot water or chemical disinfection). A wake-up time and a corresponding wake-up procedure is preferably programmed for each day of the week. If disinfection is programmed, the machine wakes up at the predetermined time to heat the water or mix the chemicals before pumping the cleaning/disinfecting liquid through the dialysis machine. The machine then rinses the cleaning/disinfecting liquid down a waste drain. If a chemical solution is utilized, the dialysis machine may be programmed to allow the chemical solution to dwell within the dialysis machine for a predetermined period before rinsing it down the drain. The apparatus includes an input/output device, a microprocessor and a non-volatile memory system for programing and storing the desired wake-up times and cleaning/disinfecting procedures. The automatic nature of the method and apparatus allow a dialysis machine operator to prepare the dialysis machine prior to leaving at the end of the day so that the machine automatically cleans and disinfects itself or starts to prepare dialysate before the start of the next day. Sensors within the dialysis machine may determine whether the machine is properly configured for the desired wake-up procedure before the operator leaves at the end of the day.

The present invention relates to a new technique for making up adialysis machine at a predetermined date and time to automatically cleanand disinfect the portion of the machine which produces and pumpsdialysate to a dialyzer for use during a patient's dialysis treatment.

CROSS REFERENCE TO RELATED INVENTIONS

This invention is related to the inventions described in U.S. patentapplications for Technique for Priming and Recirculating Fluid Through aDialysis Machine to Prepare the Machine for Use, Ser. No. 08/481,755;Graphical Operator Machine Interface and Method for Information Entryand Selection for a Dialysis Machine, Ser. No. 08/486,944; and Techniquefor Using a Dialysis Machine to Disinfect a Blood Tubing Set, Ser. No.08/481,754, all of which were filed concurrently therewith. All of theseapplications are further assigned to the assignee hereof. Thedisclosures of these applications are further incorporated herein bythis reference.

BACKGROUND OF THE INVENTION

A dialysis system is used as a substitute for the natural kidneyfunctions of a human body. The dialysis system cleans the blood of thenatural accumulation of bodily wastes by separating the wastes from theblood outside or extracorporeally of the body. The separated wastes aredischarged and the cleansed blood is returned to the body.

The dialysis system consists of a dialysis machine, a dialyzer, adisposable blood tubing set and a supply of chemicals for producing adialysate solution used within the dialyzer. The dialyzer is used withthe dialysis machine to separate the wastes from the blood. The dialyzerincludes a porous membrane located within a closed housing whicheffectively separates the housing into a blood compartment and adialysate or filtrate compartment. The blood removed from the patientflows through the disposable blood tubing set and the blood side of thedialyzer. The dialysate solution prepared from the chemicals is passedthrough the dialysate side of the dialyzer. The wastes from the bloodpass through the membrane by osmosis, ionic transfer or fluid transportinto the dialysate and, depending upon the type of dialysis treatment,desirable components from the dialysate may pass in the oppositedirection through the membrane and into the blood. The transfer of thewastes into the dialysate cleanses the blood while allowing the desiredcomponents from the dialysate to enter the bloodstream.

The transfer of blood between the patient and the dialyzer occurs withina disposable blood tubing set. The blood tubing set and the dialyzerrepresent a closed extracorporeal path through which the patient's bloodtravels. The blood tubing set includes an arterial line for drawingblood from a patient and a venous line for returning the dialyzed bloodto the patient. Before the blood tubing set and the dialyzer can be usedin a dialysis treatment, both must be primed with a sterile salinesolution to remove air from the extracorporeal circuit.

The dialysate which flows through the dialysate compartment of thedialyzer is typically prepared by the dialysis machine within adialysate flow path of the machine. The dialysis machine mixes purifiedwater with chemicals such as bicarbonate and acid within the dialysateflow path and heats the prepared dialysate before pumping it to thedialyzer. The resulting dialysate mixture has beneficial chemicalproperties which allow the dialysate to attract the waste products fromthe patient's blood and draw the waste products through the dialyzermembrane. However, the same chemical properties which allow thedialysate to perform its cleansing function also tend to attractmicroorganisms. Thus, it is typically necessary to clean and disinfectthe dialysate flow path of the dialysis machine on a daily basis beforeany patients are connected to the dialysis machine.

The cleaning and disinfecting process may take up to several hours ormore depending on the type of disinfection process used. The typicalapproach to cleaning and disinfecting a dialysis machine is for a workerto start the cleaning/disinfecting process early in the morning so thatit will be completed prior to the arrival of the first patient. However,such an approach typically requires the worker to arrive at a very earlyhour, particularly since the blood tubing set and the dialyzer can notbe connected to the dialysis machine and primed until after thedialysate flow path has been cleaned and disinfected.

The requirement of cleaning and disinfecting the dialysate flow path isoften governed by a regulatory agency and thus can not be avoided by ahospital or dialysis clinic. Therefore, although the majority of thecleaning and disinfecting process is typically performed automaticallyby the dialysis machine once it has been initiated by a worker, therequirement that the process be performed each morning, together withthe length of time required to perform the process, represents asubstantial burden on hospitals and clinics in the form of increasedlabor costs.

These and other considerations have contributed to the evolution of thepresent invention which is summarized below.

SUMMARY OF THE INVENTION

One of the significant aspects of the present invention pertains toprogramming a dialysis machine to use either hot water or a chemicalsolution to clean and disinfect the hydraulic components used to createand pump dialysate to a dialyzer during a dialysis treatment. Anothersignificant aspect of the present invention relates to programming adialysis machine to perform the cleaning and disinfecting procedure at apredetermined date and time to free a dialysis machine operator fromhaving to arrive at work at an early hour to initiate the cleaning anddisinfecting process in time to prepare the dialysis machine for thefirst patient. A further significant aspect of the present inventionrelates to allowing a dialysis machine operator to perform a chemicalcleaning and disinfection procedure at the end of a day and programingthe dialysis machine to rinse the chemical disinfectant from thehydraulic components at a predetermined time before the start of thenext day to maximize the dwell time of the chemical disinfectant withinthe hydraulic components.

In accordance with these and other aspects, the present invention may begenerally summarized as a method of "waking up" a dialysis machine at apredetermined date and time and commanding the dialysis machine toperform one of several different cleaning/disinfecting procedures. Onesuch procedure utilizes only hot water, and thus the dialysis machineawakens at the predetermined time to heat the water and pump the heatedwater through the hydraulic components of the machine. Once the heatedwater has completed cleaning and disinfecting the machine, the usedwater is directed to a waste drain for disposal. A secondcleaning/disinfecting procedure requires the dialysis machine to mix achemical cleaner and disinfectant with the water. If desired, thechemical solution may be heated by heating the water before it is mixedwith the chemicals. The dialysis machine thus awakens at thepredetermined time to mix the chemicals (and optionally heat the water)before pumping the chemical solution through the hydraulic components ofthe machine. The chemical solution may be allowed to dwell within thehydraulic lines before it is directed to the waste drain. Once thechemical solution has been disposed of, the machine will pump a waterrinse through the hydraulics to ensure that the chemicals have beenflushed from the hydraulic lines.

An alternative method of automatically cleaning the machine may be usedwhen an operator elects to perform a chemical clean/disinfect procedurein the evening after the last patient of the day has been treated. Inthat case, the chemical cleaner and disinfectant is pumped through thedialysis machine hydraulics and allowed to dwell within the hydrauliclines overnight. The machine is thus programmed to wake up at arelatively later predetermined time to rinse the used chemical solutiondown the waste drain of the dialysis machine.

The present invention also comprises a method of programing a dialysismachine to awake at a predetermined time, as well as specific apparatuswhich allow the machine to automatically wake up and perform the desiredcleaning/disinfecting procedure at the predetermined time. The methodand apparatus include using a touch screen or other input/output deviceto store the desired wake-up dates and times in a non-volatile memorysystem of the machine. A microprocessor then periodically checks thereal time against the next predetermined time to awaken the dialysismachine at the predetermined time and perform the desired procedure oncethat procedure has been retrieved from the non-volatile memory. Themethod also preferably includes placing the dialysis machine in a lowpower energy-saving mode prior to the predetermined wake-up time andafter completion of the requested wake-up procedure. A number of sensorsare preferably connected within the dialysis machine to indicate to themicroprocessor whether the machine has been properly configured forperforming the desired cleaning/disinfecting procedure at thepredetermined wake-up time.

Additional steps or apparatus may be added to enhance the basictechnique described above. For example, when the cleaning/disinfectingprocedure has been completed, the dialysis machine may provide anindication on the touch screen or other input/output device that themachine is ready for the operator to make the final preparations forconnecting a patient to the machine. Additionally, when the dialysismachine initially awakens, it may automatically perform a diagnosticself-test of its microprocessor and nonvolatile memory system beforebeginning the requested cleaning/disinfecting procedure.

Automatically waking up the dialysis machine so that it may perform theroutine cleaning and disinfecting procedure before the arrival of thehospital or clinic staff represents a beneficial savings in labor, aswell as the time and costs associated with that saved labor.

A more complete appreciation of the present invention and its scope maybe obtained from the accompanying drawings, which are briefly summarizedbelow, from the following detailed descriptions of presently preferredembodiments of the invention, and from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a dialysis machine which incorporatesthe present invention.

FIG. 2 is a generalized view illustrating a dialyzer, an extracorporealblood flow path from a patient through the dialyzer, and a dialysateflow path through the dialyzer, as are present during treatment of apatient with the dialysis machine shown in FIG. 1.

FIG. 3 is an expanded view of the dialysate flow path shown in FIG. 2(including the dialyzer), where the extracorporeal blood flow path hasbeen omitted for clarity.

FIG. 4 is a view of the dialysate flow path similar to FIG. 3, where thedialyzer has been replaced by a bypass for the purpose of cleaning andsterilizing the dialysate flow path.

FIG. 5 is a flow chart illustrating the process of programming thedialysis machine shown in FIG. 1 to automatically wake up and conduct acleaning/disinfecting procedure on the dialysate flow path according tothe present invention.

FIG. 6 is flow chart illustrating the automated process of the presentinvention which is performed by the dialysis machine shown in FIG. 1when it wakes up at a predetermined time and performs thecleaning/disinfecting procedure.

DETAILED DESCRIPTION

An example of a dialysis machine with which the present invention may beadvantageously employed is shown at 30 in FIG. 1. The dialysis machine30 includes an enclosure 32 to which are attached, or within which arehoused, those functional devices and components of the dialysis machine30 which are generally illustrated in FIG. 2. The enclosure 30 alsoincludes a conventional input/output ("I/O") device for controlling themachine 30, such as a touch-screen monitor 33 as shown in FIG. 1.

The dialysis machine 30 includes at least one blood pump 34 whichcontrols the flow of blood from a patient 36. An arterial line or tubing38 is connected through an arterial clamp 40 to a blood handlingcartridge 42. The blood handling cartridge 42 is normally retainedbehind a door 44 (FIG. 1) of the machine 30 when used, thus the bloodhandling cartridge 42 is not shown in FIG. 1. The blood pump 34 also islocated behind the door 44 adjacent to the cartridge 42. The blood pump34 in dialysis machines is typically a peristaltic pump.

Blood from the patient 36 flows through an extracorporeal flow circuitwhen the arterial clamp 40 is open and the blood pump 34 draws bloodfrom the patient 36. The blood passes through the arterial line 38 andinto an arterial reservoir 46 of the cartridge 42. The blood pump 34draws blood from the arterial reservoir 46 through a pump tubing 48which is squeezed or pinched by a rotating rotor 49 against a stationaryraceway 50, in the typical manner of peristaltic pumps. The blood withinthe pump tubing 48 which is rotationally in front of the rotor 49 ispropelled through the pump tubing 48 and into a manifold 51 of thecartridge 42. A tubing 52 conducts the blood from the manifold 51 of thecartridge 42 into a blood inlet 53 of a conventional dialyzer 54. Amicroporous membrane or other type of dialysis medium 56 divides theinterior of the dialyzer 54 into a blood chamber 58 and a dialysatechamber 60.

As the patient's blood passes through the dialyzer 54, the wasteproducts within the blood pass through the medium 56 where they mix withthe dialysate in the chamber 60. The cleansed blood then exits thedialyzer 54 through a blood outlet 61 and is then transferred through atubing 62 to a venous reservoir 64 of the cartridge 42. Any air whichmight have been unintentionally introduced into the blood is collectedand removed while the blood is in the venous reservoir 64. The bloodexits the venous reservoir 64 through a venous tubing or line 66 which,in turn, passes through an air detector 70. The air detector 70 derivessignals related to the quantity of air, if any, remaining in the venousline 66. If an excessive or dangerous amount of air is present, a venousline clamp 72 will immediately close to terminate the flow of bloodthrough the venous line 66 before the detected air reaches the patient36.

The enclosure 32 of the dialysis machine 30 also encloses the variouselements of a dialysate flow path, shown in abbreviated form in FIG. 2.The elements of the dialysate flow path include a number of differentvalves (most of which are not shown) and a dialysate pump 74 which drawsdialysate from a container 76 or from an internal supply of dialysatewhich the dialysis machine 30 has prepared from appropriate chemicalsand a supply of purified water.

The dialysate pump 74 draws the dialysate from the supply 76 anddelivers the dialysate through a dialysate supply tubing or line 78 toan inlet 79 of the dialysate chamber 60 of the dialyzer 54. Thedialysate flows past the medium 56 where it absorbs the waste productsfrom the blood in the blood chamber 58. Any beneficial components withinthe dialysate which are desired to be transferred to the blood passthrough the medium 56 and enter the blood in the blood chamber 58.

Prior to reaching the dialyzer 54, a heater 80 heats the dialysate tonormal human body temperature. Because the dialysate and the blood willreadily transfer heat across the medium 56 within the dialyzer 54, it isimportant that the dialysate be at body temperature to prevent excessiveheat transfer to or from the patient.

Dialysate containing the waste products exits the dialysate chamber 60through an outlet 81 and is removed from the dialyzer 54 through adialysate waste tubing or line 82 by operation of a waste pump 84. Thewaste pump 84 is operated at a lesser volumetric pumping rate comparedto the volumetric pumping rate of the dialysate pump 74 when it isdesired to transfer components from the dialysate into the blood byfluid transport within the dialyzer 54. The waste pump 84 is operated ata greater volumetric pumping rate compared to the volumetric pumpingrate of the dialysate pump 74 when it is desired to remove fluidcomponents from the blood by fluid transport. Both of these flow controltechniques are known as ultrafiltration and are well known to thoseskilled in the art.

The dialysate removed from the dialyzer 54 is delivered through thewaste tubing 82 to a waste drain 86. The waste drain 86 may be aseparate container which receives the used dialysate and accumulatedwaste products, or it may simply be a drain to a public sewer. Thevarious valves and pumps which control the dialysate flow path arereferred to generally as the dialysate hydraulics.

Because the blood in the extracorporeal flow path is prone to clot, itis typical to inject an anticoagulant such as heparin into theextracorporeal flow path. The typical approach to injecting theanticoagulant is to slowly deliver it from a syringe 89. A plunger 90 ofthe syringe is slowly and controllably displaced into the syringe 89 bya linear driver mechanism (not shown), which is typically referred to asan anticoagulant pump. Anticoagulant from the syringe 89 is introducedinto the manifold 51 of the cartridge 42 through a tubing 92 connectedto the syringe as shown in FIG. 2.

Tubings 94 and 96 are respectively connected to the arterial reservoir46 and venous reservoir 64 of the cartridge 42 as shown in FIG. 2.Clamps or caps (not shown) are connected to the ends of the tubings 94and 96 to selectively vent accumulated air from the reservoirs 46 and64. A saline tubing 98 is also connected to the arterial reservoir 46 sothat saline may be directly administered to the patient during treatmentin case of low blood pressure. Additionally, medicines or otheradditives may be introduced into the blood through the access tubing 94during treatment.

The reservoirs 46 and 64 and the manifold 51 of the blood handlingcartridge 42, together with the tubes 38, 48, 52, 62 and 66, arecollectively referred to as a blood tubing set ("BTS"). The BTS isdisposable and is typically thrown away after each dialysis treatment.Similarly, the dialyzer 54 is termed a disposable product, although itis not uncommon for a dialyzer to be reused with a single patient. Adialyzer will typically be reused by a patient who regularly visits thesame clinic for dialysis treatments. Following each treatment, thedialyzer is cleaned with a sterilant and is then stored until thepatient's next visit to the clinic. The dialyzer must then be thoroughlycleaned before use to ensure that the sterilant is not transferred tothe patient's bloodstream during the next dialysis treatment.

The dialysate hydraulics and the disposable BTS comprise completelyseparate flow paths separated by the membrane or medium 56 within thedialyzer 54. Prior to each dialysis treatment, the disposable BTS mustbe primed and recirculated with a sterile fluid to remove the air andestablish a stable flow within the BTS before the arterial line 38 isconnected to a patient. A technique for automatically priming andrecirculating the sterile fluid through the BTS is described in theabove-referenced U.S. Patent Application entitled Technique for Primingand Recirculating Fluid Through a Dialysis Machine to Prepare theMachine for Use, and assigned to the assignee hereof. While the BTS ischanged prior to each dialysis treatment, the dialysate hydraulics aretypically cleaned and disinfected at the beginning of each day beforethe first patient is connected to the dialysis machine 30. The dialysatehydraulics shown in abbreviated fashion in FIG. 2 are shown in slightlygreater detail in FIGS. 3 and 4, although many components of thedialysis hydraulics are still omitted (or have been shown in ageneralized manner) for the sake of clarity.

When the dialysis machine 30 creates its own supply of dialysate, asopposed to using a previously prepared supply as shown in FIG. 1, thedialysate supply 76 preferably takes the simplified form shown in FIGS.3 and 4. The dialysate hydraulics creates the dialysate by mixing a flowof purified water from source 102 with chemicals which typically includebicarbonate and acid. Bicarbonate is pumped from a source 104 by a pumplabeled at 106 as "Pump B." Similarly, acid is pumped from a source 108by a pump labeled at 110 as "Pump A." The water is preferably heated bythe heater 80 before it is mixed with the bicarbonate and acid withinthe dialysate line 78.

A number of various filters, sensors and other ancillary devices areshown generally at 112. A filter is typically necessary to remove anyimpurities from the dialysate before it enters the dialyzer 54.Additionally, the temperature, conductivity and pH level of thedialysate is sensed at 112. The sensors then control the heater 80 andthe pumps 106 and 110 to maintain the temperature and composition of thedialysate within prescribed limits. A predetermined composition of thedialysate is necessary to achieve the desired level of ionic transferbetween the blood and the dialysate within the dialyzer 54. Similarly,the temperature of the dialysate must be regulated to prevent excessiveheat transfer to or from the patient. Other ancillary equipment that maybe generally represented at 112 includes bubble traps and degassingvalves to ensure that no air bubbles are sent through the dialysate line78 to the dialyzer 54.

The dialysate pump 74 pumps the mixed dialysate through the inlet 79 andinto the dialysate chamber 60 of the dialyzer 54. The dialysate withinthe chamber 60 cleanses the patient's blood across the membrane ormedium 56 as the BTS (not shown in FIGS. 3 and 4) passes the bloodthrough the blood chamber 58 (between the inlet 53 and the outlet 61) ofthe dialyzer 54. The dialysate waste pump 84 then disposes of the useddialysate by pumping it from the dialyzer outlet 81 to the waste drain86 through the waste line 82.

As noted above, the dialysate pump 74 and the waste pump 84 may beoperated at different volumetric pumping rates when it is desired totransfer components between the dialysate and the blood by fluidtransport across the membrane 56 within the dialyzer 54. Flow sensors114 and 116 measure the respective dialysate flow rates before and afterpassage through the dialyzer 54 to control to the pumps 74 and 84. Forexample, when it is desired to transfer components from the dialysate tothe blood within the dialyzer 54, the waste pump 84 may be slowed untilthe flow sensor 116 measures a flow which is reduced a predeterminedamount in relation to the flow measured by the sensor 114.

When the dialysate hydraulics are cleaned and disinfected (e.g., at thestart of each day), the dialyzer 54 (FIG. 3) is replaced with a dialyzerbypass block 118 (FIG. 4). The bypass block 118 includes two separatechannels 120 and 122. The channel 120 connects the dialysate line 78(normally connected to the dialyzer input 79, as shown in FIG. 3) to apre-dialyzer recirculation line 124. Similarly, the channel 122 connectsthe waste line 82 (normally connected to the dialyzer output 81, asshown in FIG. 3) to a post-dialyzer recirculation line 126. The bypassblock 118 thus creates two separate recirculation loops, a pre-dialyzerloop 128 (FIG. 4) which includes the hydraulic elements "upstream" ofthe dialyzer 54, and a post-dialyzer loop 130 which includes the"downstream" hydraulic elements between the dialyzer 54 and the wastedrain 86.

The dialysis machine 30 may be programmed for several different types ofcleaning/disinfecting procedures to kill microorganisms attracted by thedialysate to the hydraulics flow path. These procedures includecirculating only heated water, circulating a chemical solution, orcirculating a heated chemical solution. If hot water alone is to beused, the heater 80 heats the water from the source 102 to apredetermined temperature. If a chemical solution is desired, the pumps106 and 110 are respectively connected to sources 125 and 126 of cleanerand disinfectant (FIG. 4), as opposed to the bicarbonate and acidsources 104 and 108 (FIG. 3) to which the pumps are respectivelyconnected during a typical dialysis procedure. The pumps 106 and 110 mixpredetermined proportions of the cleaner and disinfectant with waterfrom source 102 to create the required cleaning and/or disinfectingsolutions. If a heated chemical solution is desired, the water fromsource 102 is heated by the heater 80 before it is mixed with thechemicals. Furthermore, a sterilant solution (not shown) may be added tothe mixture by using an additional pump (not shown) to feed thesterilant into the line 78.

Once the hot water or the cleaning/disinfecting solution is prepared, itis recirculated through the pre-dialyzer recirculation loop 128comprising the dialysate line 78, the channel 120 of the bypass block118 and the pre-dialyzer recirculation line 124, as shown in FIG. 4.Additionally, a number of valves (collectively labeled with referencenumber 132) are controlled in a known manner to direct a flow of thecleaning solution from the pre-dialyzer recirculation loop 128 to thepost-dialyzer recirculation loop 130 through bypass lines 134. Upon theconclusion of the cleaning/disinfecting process, the valves 132 areagain operated in a known manner to direct the cleaning solution to thepost-dialyzer recirculation loop 130 where a waste valve 136 disposes ofthe solution down the waste drain 86. If a chemical solution is used inthe cleaning/disinfecting process, a final step of the process typicallyentails rinsing the dialysate hydraulics to ensure that the chemicalcleaner 125 and disinfectant 126 are completely washed from thedialysate line 78 and the waste line 82 before those lines are connectedto the dialyzer 54 as shown in FIG. 3.

The length of the cleaning/disinfecting process depends on whether thehot water is used alone or in combination with the chemical cleaner 125and disinfectant 126 (or with a sterilant, not shown). If hot wateralone is used, the length of the procedure will depend on the desiredwater temperature as the heater 80 must typically heat all the waterused for the procedure. Additionally, a chemical solution will often bemore effective the longer it is allowed to dwell within the respectiverecirculation loops 128 and 130. Thus, the length of time required tocomplete the cleaning/disinfecting process may vary from 30 minutes toseveral hours. This variance in time allows hospitals or clinics toutilize two different cleaning/disinfecting procedures. The firstprocedure requires an operator to perform a chemical clean/disinfectfollowing the last patient treatment at the end of the day. Thechemicals are then allowed to dwell within the hydraulic lines overnightbefore they are flushed from the system with a water rinse at the startof the next day. The other alternative is to perform the entireclean/disinfect procedure at the start of the day before the arrival ofthe first patient. Although it is preferred to clean the dialysatehydraulics at the start of the day (to kill any microorganisms which mayhave grown overnight), the present invention may be beneficially usedwith either procedure to reduce the time required to prepare thedialysis machine each morning.

The present invention includes a technique for programming the dialysismachine 30 to "wake-up" at a predetermined time each morning andautomatically clean and disinfect the dialysate hydraulics before thedialysis machine operator arrives to set up and prime the blood tubingset. If the dialysis machine 30 was filled with a chemicalcleaning/disinfecting solution after the last patient treatment, themachine 30 may be programmed to wake up and rinse the chemicals from thehydraulic lines. Alternatively, if the machine 30 has not been cleanedsince the last patient treatment, the machine may be programmed to wakeup at a relatively earlier time and perform the entire clean/disinfectprocedure.

In addition to cleaning and disinfecting the dialysis machine 30 once aday, regulatory agencies typically require that the machine 30 undergo"power-up test" which checks the machine's electronic components toensure that its memory is valid and that the microprocessor is able toexecute all the instructions that will typically be required during adialysis treatment. This power-up test is similar to the initial testperformed by computers each time they are started or rebooted. Since thedialysis machine 30 needs to be idle during the power-up test (i.e., notperforming a dialysis treatment or a cleaning or priming procedure), themachine 30 is preferably programmed to perform this test when itinitially wakes up and before it begins any other "wake-up" procedure.Should the machine detect a problem during the power-up test, it willshut down and display an appropriate error message on the display 33(FIG. 1) so that proper corrective action may be taken by the operatorupon his or her arrival.

Once the machine 30 has passed the power-up test and has been cleanedand disinfected, it may automatically perform other "wake-up"procedures. For instance, if the machine had been previously disinfectedand thus required only a rinse at wake-up, it may optionally beginpreparing dialysate for use in the first dialysis treatment of the day(provided the proper connections to the bicarbonate and acid sources 104and 108 have previously been made). Alternatively, upon the conclusionof the full clean/disinfect process, the machine 30 may enter alow-power mode and wait for an operator to initiate the procedure forpriming the blood tubing set.

The machine 30 is preferably programmed at one time for the desiredwake-up times (and the corresponding wake-up functions) for each day ofthe week. For example, the machine may be programmed through the touchscreen monitor 33 as described more fully in the above-referenced U.S.Patent Application for a Graphical Operator Machine Interface and Methodfor Information Entry and Selection for a Dialysis Machine, assigned tothe assignee hereof.

FIG. 5 illustrates a preferred method for programing the machine 30. Anoperator first selects at 140 the day of the week which will beprogrammed. The operator next enters at 142 the time the machine is towake-up from a low power mode and initiate both the power-up test andthe "wake-up" procedure. The operator next chooses at 144 the type ofprocedure which is to be performed. For example, if the clinic choosesto chemically clean and disinfect the dialysis machine 30 at the end ofthe day and allow the chemicals to dwell within the machine overnight,the operator would choose to perform only a water rinse at wake-up. Theoperator may also optionally prepare the machine as shown in Fig. 3 andprogram the machine to begin preparing dialysate upon completion of therinse procedure. Alternatively, if the machine was not cleaned after thelast patient treatment, the operator would choose to perform the entirecleaning and disinfecting process at wake-up.

After entering the day, time and type of procedure to be performed, themachine 30 preferably prompts the operator to confirm his or her choiceat 146, at which point mistakes in either the wake-up time or the choiceof procedure may be corrected. Once the entry is confirmed, the machine30 stores the entry into its nonvolatile memory at 148 so that theinformation will not be lost in the case of a power loss. The machine 30is then similarly programmed for the remaining days of the week, and theprogrammed information is retained in the machine's non-volatile memoryuntil such time as the programmed information needs to be changed.

The process of placing the machine 30 in a low power or "sleep" mode andthen waking the machine at the predetermined date and time is shown inFIG. 6. At the end of the day (i.e., after the last patient has beentreated), the dialysis machine operator prepares the machine for thefollowing day by either performing the chemical clean/disinfectprocedure (and optionally preparing the machine for dialysatepreparation), or by connecting the dialysate bypass block 118 as shownin FIG. 4 and connecting the pumps 106 and 108 to the sources 125 and126 of cleaner and disinfectant, respectively. The operator thenindicates to the machine at 150 (via the touch screen 33) that it is theend of the day. The machine 30 immediately checks its memory at 152 todetermine what wake-up procedure it will be required to perform thefollowing day. The machine 30 next conducts a connectivity check at 154by polling several sensors connected within the dialysate hydraulics todetermine whether the proper connections have been made to allow it toautomatically perform the requested procedure without any additionalhuman intervention. The sensors include a sensor 156 connected to Pump B(106) and a sensor 158 connected to Pump A (110) which indicate whetherthose pumps have been properly connected to the sources of cleaner anddisinfectant 125 and 126 (or to the sources of bicarbonate and acid 104and 108 if the machine is to wake up and prepare dialysate).Additionally, a sensor 160 determines whether the dialyzer bypass block118 has been properly connected in place of the dialyzer 54.Furthermore, if a sterilant source and pump (not shown) are also used incleaning the machine, an additional sensor (not shown) may be connectedto the sterilant pump to ensure proper connectivity.

If the sensors indicate that a connection has been forgotten orincorrectly made, the machine 30 will immediately notify the operator at162 of the problem (via the touch screen 33). This connectivity check ispreferably done at the end of the day rather than at the wake-up time toprevent the machine from waking up before the arrival of any dialysismachine operators and discovering it was not properly connected for thedesired procedure (thereby delaying the wake-up process and the timewhen the machine will be available for the first patient).

If the connectivity check confirms the proper connections have beenmade, the machine enters a low power mode at 164 to conserve energyuntil its preappointed wake up time. During the low power or "sleep"period, the machine periodically performs checks at 166 of the real timeagainst the next programmed wake-up time stored in its memory. Themachine then determines at 168 whether the wake-up time has beenreached. If not, it loops back to 166 to continue performing the timechecks. When the wake-up time is reached at 168, the machine performsthe power-up test at 170. Alternatively, the machine 30 could performthe power-up test at a predetermined interval before the wake-up time(e.g., if the power-up test takes two minutes, the test could beperformed two minutes before the wake-up time).

Upon conclusion of the power-up test at 170, the machine retrieves thedesired wake up procedure from its non-volatile memory at 172. Adetermination is made at 174 as to which procedure is to be performed.If a water rinse has been programmed at 144, the machine 30 willinitiate the rinse cycle at 176. If a clean/disinfect procedure has beenprogrammed, the machine 30 will begin mixing the solution (or heatingthe water) at 178 as required to perform the procedure. Similarly, ifthe machine has been programmed to prepare dialysate, it will beginmixing the chemicals (FIG. 3) and heating the water at 179. Upon theconclusion of the wake-up procedure, the machine will notify theoperator at 180 that the power-up test and the cleaning/disinfectingprocess have been successfully completed so that the bypass block 118may be removed from the machine 30 in preparation for priming thedialyzer 54 and the blood tubing set.

The present invention thus represents a great savings in time todialysis machine operators who must initially prepare a dialysis machinefor patient treatment. For example, if a dialysis machine operatorpreviously had to start work at 5:00 a.m. in order to clean anddisinfect a number of dialysis machines before the arrival of patientsat 8:00 a.m., those same machines could use the present invention towake themselves up at 5:00 a.m. and automatically perform the clean anddisinfect procedure. The operator would then only have to arrive earlyenough to prime the dialyzer and blood tubing set before connecting thedialysis machine to the first patient. The labor saved by the presentinvention thus represents a great savings in both time and costs for ahospital or a dialysis clinic.

A presently preferred embodiment of the present invention and many ofits improvements have been described with a degree of particularity.This description is a preferred example of implementing the invention,and is not necessarily intended to limit the scope of the invention. Thescope of the invention is defined by the following claims.

The invention claimed is:
 1. A method of cleaning and disinfecting adialysis machine with hot water, said dialysis machine including adialysate preparation line and a waste disposal line adapted to beconnected to a dialyzer, and said method comprising the stepsof:connecting a bypass line between the dialysate preparation line andthe waste disposal line to transmit the heated water between thedialysate preparation and waste disposal lines; connecting a firstrecirculation line to the dialysate preparation line and connecting asecond recirculation line to the waste disposal line to recirculate thehot water through both the dialysate preparation and waste disposallines; and programing the dialysis machine to perform the followingsteps at a predetermined date and time: heating a supply of water;pumping the heated water through the dialysate preparation line, thebypass line, the waste disposal line and each of the recirculationlines; and pumping the heated water down a waste drain within the wastedisposal line to dispose of the heated water.
 2. A method as defined inclaim 1, wherein the dialysis machine is programmed to include anadditional step of reducing power to the dialysis machine at the end ofthe day to conserve energy until the predetermined date and time.
 3. Amethod as defined in claim 2, wherein the dialysis machine is programmedto include an additional step of conducting a diagnostic test prior toreducing power to the dialysis machine to ensure that the bypass andrecirculation lines are properly connected.
 4. A method as defined inclaim 2, wherein the dialysis machine is programmed to include anadditional step of performing a diagnostic test of a computer processorand memory system prior to heating the supply of water.
 5. A method asdefined in claim 1, wherein the dialysis machine is programmed toinclude an additional step of providing an indication that the dialysismachine has been cleaned and disinfected after the heated water has beendisposed of down the waste drain.
 6. A method as defined in claim 5,wherein the dialysis machine is programmed to include an additional stepof reducing power to the dialysis machine after providing the indicationthat the dialysis machine has been cleaned and disinfected.
 7. A methodof cleaning and disinfecting a dialysis machine with a chemicalsolution, said dialysis machine including a dialysate preparation lineand a waste disposal line adapted to be connected to a dialyzer, andsaid method comprising the steps of:connecting a bypass line between thedialysate preparation line and the waste disposal line to transmit thechemical solution between the dialysate preparation and waste disposallines; connecting a first recirculation line to the dialysatepreparation line and connecting a second recirculation line to the wastedisposal line to recirculate the chemical solution through both thedialysate preparation and waste disposal lines; connecting a chemicalsource to the dialysate preparation line; and programing the dialysismachine to perform the following steps at a predetermined date and time:mixing chemicals from the chemical source with water from a water sourceto create the chemical solution within the dialysate preparation line;pumping the chemical solution through the dialysate preparation line,the bypass line, the waste disposal line and each of the recirculationlines; pumping the chemical solution down a waste drain within the wastedisposal line to dispose of the chemical solution; and rinsing thedialysis machine with water to remove the chemicals from the dialysatepreparation line, the bypass line, the waste disposal line and each ofthe recirculation lines.
 8. A method as defined in claim 7, wherein thedialysis machine is programmed to include an additional step of reducingpower to the dialysis machine at the end of the day to conserve energyuntil the predetermined date and time.
 9. A method as defined in claim8, wherein the dialysis machine is programmed to include an additionalstep of polling sensors connected to the chemical source and therecirculation lines prior to reducing power to the dialysis machine toensure that the recirculation lines and the chemical source are properlyconnected.
 10. A method as defined in claim 7, wherein the dialysismachine is programmed to include an additional step of allowing thechemical solution to dwell within the dialysate preparation line, thebypass line, the waste disposal line and each of the recirculation linesfor a predetermined time before pumping the chemical solution down thewaste drain.
 11. A method as defined in claim 8, wherein the dialysismachine is programmed to include an additional step of performing adiagnostic test of a computer processor and memory system prior tomixing the chemicals and the water to create the chemical solution. 12.A method as defined in claim 7, wherein the dialysis machine isprogrammed to include an additional step of providing an indication thatthe dialysis machine has been cleaned and disinfected after the step ofrinsing the dialysis machine with water.
 13. A method as defined inclaim 12, wherein the dialysis machine is programmed to include anadditional step of reducing power to the dialysis machine afterproviding the indication that the dialysis machine has been cleaned anddisinfected.
 14. A method as defined in claim 7, wherein the dialysismachine is programmed to include an additional step of heating the waterprior to mixing the chemicals with the water to create the chemicalsolution.
 15. A method as defined in claim 7, wherein the steps prior torinsing the dialysis machine with water are performed prior to thepredetermined date and time.
 16. A method as defined in claim 10,wherein the steps prior to rinsing the dialysis machine with water areperformed prior to the predetermined date and time.
 17. A method asdefined in claim 16, wherein the dialysis machine is programmed toinclude an additional step of providing an indication that the dialysismachine has been cleaned and disinfected after the step of rinsing thedialysis machine with water.